Bulletin of the United States Geological SurveyThe Survey., 1896 |
Dentro del libro
Resultados 1-5 de 100
Página 55
... ROCKS . The whole region under consideration is covered under the drift with Cretaceous rocks belonging to the Fox Hills and Pierre formations . No traces of older rocks are found nearer than the Sioux quartzite near Mitchell and the ...
... ROCKS . The whole region under consideration is covered under the drift with Cretaceous rocks belonging to the Fox Hills and Pierre formations . No traces of older rocks are found nearer than the Sioux quartzite near Mitchell and the ...
Página 27
... Rocks , 4 miles above City Point . EXPOSURE AT POINT OF ROCKS . The exposure of the Potomac formation at Point of Rocks is much the most extensive one on the Appomattox , and may be taken as giving a fair representation of the character ...
... Rocks , 4 miles above City Point . EXPOSURE AT POINT OF ROCKS . The exposure of the Potomac formation at Point of Rocks is much the most extensive one on the Appomattox , and may be taken as giving a fair representation of the character ...
Página 29
... Rocks . The top of the grit shown in the bluff has evidently lost much from erosion . It is cut down till it presents an uneven , undulating , and sometimes channeled surface . At the ... Rocks , FONTAINE . ] 29 EXPOSURE AT POINT OF ROCKS .
... Rocks . The top of the grit shown in the bluff has evidently lost much from erosion . It is cut down till it presents an uneven , undulating , and sometimes channeled surface . At the ... Rocks , FONTAINE . ] 29 EXPOSURE AT POINT OF ROCKS .
Página 30
... Rocks this bed crops out in a ravine called Deep Bottom , a name also given to a locality on the James River below Dutch Gap . The top of the greensand bed here is considerably below the level of the top of the Potomac at Point of Rocks ...
... Rocks this bed crops out in a ravine called Deep Bottom , a name also given to a locality on the James River below Dutch Gap . The top of the greensand bed here is considerably below the level of the top of the Potomac at Point of Rocks ...
Página 38
... rocks that are of the Huronian type ; that is , they are composed of such fine - grained rocks as argillite , chlorite - schist , mica slate , fine - grained mica - schist , felsite , etc. Such rocks do 38 [ BULL . 145 . THE POTOMAC ...
... rocks that are of the Huronian type ; that is , they are composed of such fine - grained rocks as argillite , chlorite - schist , mica slate , fine - grained mica - schist , felsite , etc. Such rocks do 38 [ BULL . 145 . THE POTOMAC ...
Otras ediciones - Ver todas
Términos y frases comunes
acid apatite augite beds biotite bluff Bull California Cambrian Carboniferous chlorite clay balls Coal cobbles color Contains plagioclase County Creek Cretaceous deposits Describes the occurrence Devonian dike Discusses east Eocene erosion exposures feldspar figs folio fossils Geology Glacial gneiss gold granite gravel gray groundmass H₂O Harris hills hornblende Iowa iron James Jour K₂O Kansas kaolin Keyes L. G. Eakins Lake layers lignite limestone London magnetite masses material Matthew Merrill miles Miller and Gurley minerals Missouri moraine mottled Mountain Newberry olivine orthoclase Paleontology-Continued Paleozoic Paris plagioclase Pleistocene porcelain portion Potomac formation pottery pre-Cambrian Proc quartz quartzite record region Rept Rhyolite River rocks sand sandstone sandy clay Scudder Silurian SiO2 species stones strata Surv Tertiary TiO2 Trace Trans Turner U. S. Geol Ulrich Undet Valley W. F. Hillebrand Weed and Pirsson Whiteaves Whitfield Winchell and Schuchert
Pasajes populares
Página 32 - REPORT ON THE CLAY DEPOSITS of Woodbridge, South Amboy and other places in New Jersey, together with their uses for firebrick, pottery, &c.
Página 89 - PRIME'S POTTERY AND PORCELAIN. Pottery and Porcelain of All Times and Nations. With Tables of Factory and Artists' Marks, for the Use of Collectors. By WILLIAM C. PRIME, LL.D. Illustrated. 8vo, Cloth, Uncut Edges and Gilt Tops, $7 00 ; Half Calf, $9 25. (In a Box.) CESNOLA'S CYPRUS.
Página 34 - Report on the country in the vicinity of Red Lake, and part of the basin of Berens River, Keewatin.
Página 110 - MONTFORT. Five Page Illustrations. The History of the Tea-Cup : with a Descriptive Account of the Potter's Art. By the Rev.
Página 29 - Friedel ° indicates a means for determining the true weight of water lost by minerals behaving like the zeolites, even without collecting the water lost, namely, by driving out of the dehydrated and weighed mineral, under proper precautions, any air it may have absorbed in the process of drying and cooling, and collecting and measuring this air and thus finding its weight, which, added to the apparent loss, gives the true contents in water.
Página 22 - CRUSHING. For accurate analyses the use of steel power crushers and mortars is out of the question because of the danger of contamination by particles of metal and the impossibility of cleansing the roughened surfaces after they have been in use a short time. Extraction, by the aid of a magnet, of steel particles thus introduced into the powder is quite inadmissible, since the rocks themselves, almost without exception, contain magnetic minerals.
Página 61 - If, therefore, on evaporation of the filtrate, much iron is indicated, the gelatinization may well be due to olivine alone or in part, and then the quantitative relation of silica to iron plus magnesium should be ascertained. It must also be borne in mind that any other very soluble silicates present will be more or less affected, and that apatite is largely or wholly dissolved. It is possible that still more dilute nitric or perhaps some other acid may exert a slighter solvent action on olivine...
Página 20 - Survey was there to be found in the light of modern methods, a satisfactory exposition of the procedures to be followed or the precautions to be observed, especially in the search for some of the rarer constituents or those which, without being rare, have been of late years recognized as occurring persistently in small amounts. It was not the intention to .make the chapter on rock analysis in...
Página 28 - It had regained 1J per cent of its original weight, although the desiccator was tightly closed and the crucible covered, showing apparently a drying power superior to that of the acid. A specimen of tyrolite was found on one occasion to lose 10.34 per cent at 280°, and on another occasion 14.33 per cent.
Página 49 - ... as ZrO2. Certainty as to its identity can be had by again bringing it into solution, precipitating by ammonia, dissolving in hydrochloric acid, evaporating to a drop or two, and testing with turmeric paper or by a microchemical reaction. With the very smallest amounts no color can be obtained by this turmeric-paper test, which, however, responds readily to as little as 1 milligram of dioxide and with proper care for as small an amount as 0.3 milligram (Dr.